WaterVerge

Is Cowley, WY Tap Water Safe to Drink?

Graded A-, with 6 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓

800 residents served 1 water system PWSID: WY5600206
Overall Score
86.5 / 100
Violations
6 active
Last Updated
May 2026
Source
Groundwater
#18 of 65 in Wyoming Top 30% nationally
Local Government
Moderate data confidence
Reviewed by WaterVerge Editorial Team · Last updated May 2026
A-GRADE
Water Quality Grade
86.5/100
waterverge.com
A- 86.5/100

Cowley, WY — Water Quality Report

Cowley's drinking water received a grade of A- (86.5 out of 100), indicating good water quality. The city's 1 water system serves approximately 800 residents using groundwater.

Lead levels were measured at 3.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.

The system has 46 violations on record, including 4 health-based violations. 6 remain unresolved.

Data last updated: May 2026 · Source: EPA SDWIS, UCMR 5
Analysis

What to know about Cowley's water

Cowley ranks #18 out of 65 cities in Wyoming for water quality, placing it mid-range in the state.

Cowley relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.

As a small community water system, Cowley may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.

Quality Breakdown

Water quality score

See methodology →
86.5 out of 100 Grade A-
A: 90-100
B: 74-89
C: 60-73
F: <50
How is this calculated?
Violations
36.5/45
B
Historical violation record including health-based and monitoring violations.
Lead & Copper
20/20
A
Lead at 3.0 ppb (90th percentile).
Contaminants
17/20
B
PFAS + legacy contaminant analysis.
Compliance
8/10
B
Monitoring and reporting compliance with EPA regulations.
Source Risk
5/5
A
Water source: Groundwater.
Water Safety

Is Cowley, WY water safe to drink?

Concerns Identified

Cowley's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (86.5/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 800 residents using groundwater (wells).

6
Active Violations
3.0 ppb
Lead (90th %ile)
1 event
Disaster History

Recent water quality updates for Cowley

A timeline of significant water quality events, violations, and data updates.

Update
Water quality data updated

Latest EPA compliance and testing data incorporated into Cowley's water quality assessment. Grade: A- (86.5/100).

Violation
1 drinking water violation recorded

Contaminants: E. COLI.

Violation
1 drinking water violation recorded

Contaminants: Lead and Copper Rule.

Violation
1 drinking water violation recorded

Contaminants: Lead and Copper Rule.

Disaster
SEVERE STORMS, FLOODING & MUDSLIDES

Federal disaster declaration (FEMA DR-557). Flood event — may have impacted local water infrastructure.

Key contaminant findings

Based on the most recent EPA sampling data for Cowley's water supply.

Lead Within Limits
Detected: 3.0 ppb Limit: 15 ppb (EPA Action Level)

Well within EPA limits.

Violation history

Cowley's water system has 46 total violations on record, including 4 health-based violations. 6 remain unresolved. 3 violations were issued in the last 5 years.

MRTTMCL
Most recent violations:
Sep 2025 E. COLI Open
Dec 2024 Lead and Copper Rule Open
Dec 2021 Lead and Copper Rule Open
Nov 2019 Groundwater Rule Open
Jan 2017 Groundwater Rule Open

Flood & environmental risk

Big Horn County has experienced 1 federally declared disaster since 1978. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Shoshone River.

SEVERE STORMS, FLOODING & MUDSLIDES
Flood FEMA DR-557

Where does Cowley's water come from?

Cowley's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 800 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Shoshone River (river).

What Cowley residents can do

Install a water filter

Recommended: NSF-certified water filter. This addresses the specific contaminants found in Cowley's water.

Request your utility's CCR

Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.

Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.

Contaminant Alerts

Top contaminants to know

View all ↓
Lead (90th percentile)
Inorganic / Heavy Metal
Safe
3.0 ppb
EPA Action Level: 15 ppb · 20% of limit
Safe Level
Compliance Record

Violation summary

46
Total violations
4
Health-based
6
Active / unresolved
Sep 2025
Most recent violation
Compliance Record

Violations & advisories

46 Total
6 Active
4 Health-based
40 Resolved
Violations by category
Volatile Organic Chemicals
21
Total Coliform Rule
7
Inorganic Chemicals
6
Ground Water Rule
3
Nitrate Rule
3
Sep 2025 Active
E. COLI
Monitoring & Reporting
Monitoring & Reporting 0
Dec 2024 Active
Lead and Copper Rule
Monitoring & Reporting
Monitoring & Reporting 0
Dec 2021 Active
Lead and Copper Rule
Monitoring & Reporting
Monitoring & Reporting 0
Nov 2019 Active
Groundwater Rule
Treatment Technique
Health-Based Health 0
Jan 2017 Active
Groundwater Rule
Treatment Technique
Health-Based Health 0
Active
Compliance Violation
Monitoring 0
Jan 2006 Resolved
Nitrate-Nitrite
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2006
Jan 1999 Resolved
Benzene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
Vinyl chloride
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
cis-1,2-Dichloroethylene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
Tetrachloroethylene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
Toluene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
1,2,4-Trichlorobenzene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
1,1,2-Trichloroethane
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
1,1-Dichloroethylene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
DICHLOROMETHANE
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
Styrene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
o-Dichlorobenzene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
Trichloroethylene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Jan 1999 Resolved
trans-1,2-Dichloroethylene
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 1999
Showing 20 of 46 violations
Industrial pollution

Top industrial polluters within 10 miles of Cowley

Industrial polluters nearby

Reported releases to surface water by facilities near Cowley, ranked by pounds discharged annually.

Total reported releases to surface water: 107 lbs

FacilityTop chemicalTo surface water (lbs/yr)Distance
WESTERN SUGAR COOPERATIVE LOVELL FACTORY
Food · WESTERN SUGAR COOPERATIVE
LOVELL, WY82431
Ammonia1074.4 mi
WYOMING LIME PRODUCERS
Nonmetallic Mineral Product · DAKOTA COAL CO
FRANNIE, WY82423
9.4 mi
CETCO
Other · MINERALS TECHNOLOGIES INC
LOVELL, WY82431
7.1 mi

Source: EPA Toxic Release Inventory (TRI) 2023

Environmental Risk

Drought conditions

D2 — severe drought

Big Horn County is currently in D2 (severe drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.

12
Weeks at D2+ (current streak)
35.0%
Months in D2+ (last 30y)
12
Weeks at D2+ (last 5y)

Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.

Environmental Risk

Flood & disaster history

1
Declared disasters
May 1978
Most recent
Flood
Most common type

Big Horn County has experienced 1 federally declared disaster since 1978. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.

May 1978
SEVERE STORMS, FLOODING & MUDSLIDES
Flood FEMA #557

Full contaminants report

Contaminant Detected Level EPA Limit Unit Category Status
Lead (90th percentile) 3.0 15 ppb Inorganic Safe
Data source: EPA SDWIS, UCMR 5, local utility CCR.

Lead level trend (90th percentile)

EPA action level: 15 ppb
Lead has decreased by 2.0 ppb from 2006 (5.0 ppb) to 2024 (3.0 ppb).
Infrastructure

Water source & infrastructure

Primary Source
Groundwater
Operator
Local Government
Population Served
800
Water Systems
1
Water Source

Where Cowley's water comes from

Groundwater

Cowley's drinking water is drawn from underground aquifers through wells.

Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.

Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.

The system is operated by local government ownership and serves approximately 800 people through 1 water system.

Local Hydrology

Water bodies near Cowley

Cowley is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.

Shoshone River
river
Infrastructure

Water systems serving Cowley

System Name PWSID Population Source
COWLEY, TOWN OF WY5600206 800 GW
Regional Comparison

How Cowley compares

Full Wyoming rankings →

Cowley's score of 86.5/100 is above the average of 55/100 among major Wyoming cities. It outscores 10 of 10 nearby cities.

Cowley (this city)
86.5
Cheyenne
30.8
Casper
41.8
Gillette
44.5
Laramie
55.2
Jackson
43.2
Wyoming avg
55
City Profile

About Cowley, WY

Economic Profile
$73,214
Median Income
$205,421
Median Home Value
$1,069/mo
Median Rent
3.2%
Unemployment
Community
31
Median Age
295
People / sq mi
30.1%
College Educated
89.1%
Homeownership
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Frequently asked questions

Is Cowley, WY tap water safe to drink?

Cowley's water quality earned a grade of A- (86.5/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #18 out of 65 cities tested in Wyoming.

What contaminants are in Cowley's water?

Lead was measured at 3.0 ppb (90th percentile). 46 violations are on record.

How is Cowley's water quality grade calculated?

The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.

Do I need a water filter in Cowley?

Based on current data, basic filtration should suffice for additional peace of mind.

Where does Cowley's water come from?

Cowley's water is sourced from Groundwater. The city has 1 water system serving approximately 800 residents.

What health violations has Cowley's water system had?

Cowley has 4 health-based violations on record. The most recent violation was recorded in September 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 6 violations remain unresolved.

Is Cowley's groundwater at risk of contamination?

Cowley uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 46 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.

How does Cowley's water compare to other cities?

Cowley ranks #18 out of 65 cities in Wyoming (better than 72% of state cities) and #4689 out of 15744 cities nationally (70th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.

Does Cowley's small water system affect quality?

Cowley's system serves approximately 800 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 46 violations on record.